1. Field of the Invention
This invention relates to adjustable light fixtures and means for suspending light fixtures.
2. Description of the Prior Art
The display industry, particularly display personnel for department stores, has been seeking a single light fixture which is adjustable both to give general illumination and to direct light at an object at a variety of angles. Thus, the desired single fixture could be used to light a general overall area or could be used as an accent light. In the past when directing light toward an object to emphasize various features of that object, it has often been necessary to move the object with respect to the light since the fixture was not quickly and easily adjustable. In addition, many times two different light fixtures were required to provide general illumination in addition to an accent light. At least three United States patents have been granted for light fixtures. They are: U.S. Pat. No. 2,855,503 to Gerstel, U.S. Pat. No. 3,263,072 to Kruger and U.S. Pat. No. 3,381,123 to Docimo.
From the above background, it can be seen that there has been a need for a light fixture which could be quickly and easily adjusted to light a general area and to direct light at an object at various angles. The fixture should be adjustable in the vertical direction. In addition, the light should be rotatable about a vertical axis and pivotable about a horizontal axis. The light should be adjustable both when it is recessed in the ceiling and when it is extended from the ceiling. The suspension means for the light should be equally adaptable to incandescent and mercury lighting elements. This basic need has been partially satisfied by the adjustable light fixture shown and described by U.S. Pat. No. 3,660,651 to Miles (1972). However, additional problems have arisen, specifically, with regard to the use of mercury lights. Mercury lights are characteristically heavier than the incandescent light for which the adjustable light fixture of U.S. Pat. No. 3,660,651 was designed. In addition, mercury lights have a high rate of heat dissemination relative to incandescent lights and in addition have a violent termination of life often accompanied by a cracking or disintegration of the lighting elements. Therefore, in addition to the generally increased weight due to the mercury lighting element it has been found desirable to add a glass lens to the lighting fixture to prevent heat loss from the light fixture and to prevent glass from accidentally being discharged during a particularly violent termination of a mercury lighting element. The result of the use of mercury lighting element and the addition of a lens has been a general increase in the weight of the suspended unit. Therefore the toggle arm arrangement described by U.S. Pat. No. 3,660,651 has not proven satisfactory for the increased weight.